Gallup: Tied

Barack Obama's lead in the Gallup tracking poll -- which once reached 7% after the convention -- has vanished.

Among registered voters, the president and Mitt Romney are now tied, 47%-47%.

Meanwhile, in Rasmussen's tracking poll, Obama currently holds a 2% lead, which is actually a slight jump. Last week, Romney erased Obama's convention bounce in Rasmussen's poll.

Right now, we're seeing a divide -- The race is essentially even, nationally, but Obama's lead has been growing in swing states. That was confirmed most decisively in Fox News' slate of swing state polls released today.

To a lesser degree, that divide is one we've seen this entire cycle. Obama performs slightly better in swing states than in national polls.

Some possible reasons:

a. Swing state economies are either hotter than the nation's, or are moving in the right direction.

b. Obama's summer financial advantage was directed toward swing states; thus, Obama didn't bounce nationally from his TV ads, but only in the battlegrounds. That would help explain why he's doing better in swing states than nationally.

c. It could be that Obama is just a stronger candidate than Romney, and as the two stump in these states, Obama's natural gifts give him the boost.

Of course, just like a good 3 Stooges movie or 19th century alliance of Russia, Prussia, and Austria, all three forces could be playing a role.